Bis(2-pyrrolemethyl) disulfide and its n, n&#39;-dimethyl derivative



951,848 Bisa-PYRRoLnMErHYL .nrsULFiDE AND rrs N,N-DIMETHYL DERIVATIVE Lee. Nutting Berkeley, and Robert M. Silverstein and Chester M. Himel, Menlo' Park, Calif., assignors to Hills Bros. Coiiee, Inc 'San Francisco, Calif., a corporation of California No Drawing. Filed Nov. 4, 1955, Ser. No. 545,134

2 Claims. (Cl. 260-313) This invention relates to organic compounds and has particular reference to new organic disulfides and their preparation.

This invention has as an object the preparation of new organic compounds. A further object is the preparation of a new class of organic disulfides. Yet another object of this invention is the preparation of a new class of compounds, consisting of bis-heterocyclic disulfides wherein the hetero-atom is nitrogen.

Other objects and advantages of this invention it is believed will be readily apparent from the following detailed description of preferred embodiments thereof.

These and other objects are accomplished by the fol lowing invention wherein heterocyclic mercaptans are oxidized and wherein heterocyclic aldehydes are reacted With ammonium sulfides, the resulting reaction products being new compounds generically defined as bis-heterocyclio compounds wherein the hetero-atom is nitrogen and wherein the two heterocyclic nuclei are linked together by a substituent having the general formula -RSSR-, where R and R are alkylene radicals, either the same or different, each substituted on a nuclear carbon atom.

The invention is illustrated by the following examples:

a. To 5.0 g. of Z-pyridyl carbinol in 30 ml. of ether, stirred and cooled in an ice bath, was added ml. of thionyl chloride in ml. of ether. After 0.5 hour, the ether and excess thionyl chloride were removed with a water pump leaving a solid residue.

b. The above residue was refluxed for one hour with 4.4 g. of thiourea in 30 ml. of 95% ethanol. A solution of 5.0 g. of sodium hydroxide in ml. of water was added, and refluxing was continued for one hour. The solution was neutralized with carbon dioxide and extracted with ether. The residue from the ether solution was distilled at 10 mm. at a head temperature of States atent 2,951,848 Fatented Sept. 6, 1960 2 s7-s9 c. The distillate (2-pyridylmethyl mercaptan) weighed 3.2 g., and gave the following analytical values:

Calculated, Found, Percent Percent c. To asolution of 0.5 g. of 2-pyridylmethyl mercap :tan in 10ml. of chloroform wasadded 0.27 i g. of iodine. The mixture was shaken at room temperature for one hour, and the precipitate was filtered. The precipitate was shaken with sodium hydroxide solution and extracted with chloroform. The residue, impure bis-(2- pyridylmethyl) disulfide, was purified by dissolving in ether, passing in hydrogen chloride, and recrystallizing the hydrochloride. The compound was regenerated by shaking with alkali, and extracting with ether. The ether residue, a pale yellow viscous oil, was crystallized to provide a product having a melting point of 38.5- 39.5 C. and the following analytical values:

Calculated, Found.

Percent Percent Carbon 58. O 57. 0 Hydrogen 4. B4 4. 93 Sulfur 25. 8 25. 8

Other oxidizing agents than iodine, such as, for e."- ample, ferric chloride, lead peroxide, hydrogen peroxide, and copper sulfate, may be used for the oxidation of the mercaptan compounds.

EXAMPLE 2 Bis-(Z-pyrrolemethyl) disulfide Calculated, Found, Percent Percent Carbon 53. 5 53.6 Hydrogen 5. 4O 5. 50

EXAMPLE 3 Bis-(N-methyl-2-pyrrolemethyl) disulfide 5H3 6H3 6H3 N-rnethyl-2-pyrrolealdehyde was treated with ammonium sulfide in the same manner as was 2-pyrrolealdehyde in the previous preparation. Recrystallization from petroleum ether (B.P. 65-110" C.) gave a product melting at 8687 C. with the following analytical values:

Calculated, Found,

Percent Percent;

Carbon 57. 2 57. 4 Hydrogen 6. 34 6. 37

While in the specific examples set forth above the substituent RSS-R'- is substituted on nuclear carbon atoms at position 2, such substitution may also i take place at position 3 in the case of five-membered heterocyclic nuclei and also at positions 3 and 4 in the case of six-membered heterocyclic nuclei. Moreover, the heterocyclic nuclei may contain on nuclear carbons organic residue substituents in addition to the R-SS--R'-- substituents. Examples of symmetrical compounds containing such additional substituents are:

Bis-(2-methyl-4-pyridylmethyl) disulfide (N/ -oH2s- CH3 2 Bis-2-(3-mezhyl-5-ethyl S-pyrrolethyl) disulfide H 2 Bis-(N-methyl-3,5-diphenyl Z-pyrrolemethyl disulfiae stituent, such as, for example:

2-pyrr0lemethyl N-methyl 2-pyrr0lemethyl disulfide H UCHZSSCH2 y N-methyl-Z-pyrrolemethyl Z-pyr'idylmethyl disulfide Additionally, the invention includes compounds which are unsymmetrical from the standpoint that the substitution of the RfiSS-R'- substituent occurs on position 2 on one hetcrocyclic member and on position til.

(2-pyridyl)methyl 3(2-pyridyl)propyl disulfide (Z-pyrrole) methyl Z-m-ethyl-Z-(S-methyl-Lpyrrole) ethyl disulfide H CH;

The new compounds of this invention are particularly useful as flavoring agents for foods and beverages. For example, 1 part by weight of each of the following com pounds: bis-(Z-pyrrolemethyl) disulfide; bis (3-indolemethyl) disulfide- (disclosed in our copending application Serial No. 525,354, filed July 29, 1955, now abandoned, entitled Condensed Ring Heterocyclic Disulfides); bis-( 3-indolemethyl) sulfide (disclosed in our copending application Serial No. 525,353, filed July 29, 1955, now abandoned, entitled Heterocyclic Sulfides and Their Preparation); =bis-2-fur'fur-yl sulfide (also disclosed in said copending application Serial No. 525,353); 2-furfuryl isothiocyanate (disclosed in our copending application Serial No. 525,355, filed July 29, 1955, now Patent No. 2,905,- 701, entitled Heterocyclic Isothiocyanates and Their Preparation); 2-thenyl isothiocyanate (also disclosed in said copending application Serial No. 525,355); comprising a total of 100 mg. was dissolved in 900 mg. of a solvent such as fu-rfuryl alcohol. Portions of this solution may be directly added to a prepared cereal-based beverage such as Instant Postum to enhance the flavor thereof, or similar results may be obtained by incorporating the flavoring agent during the manufacture of the cereal-based beverage concentrate, such as by adding it to the liquid material prior to the final drying step. For example, when flavoring the prepared cereal-based beverage 12 mg. of the furfuryl alcohol solution are added to 100 cc. of beverage containing 1.5% soluble and dispersi'ble solids. When using the furfuryl alcohol solution in the manufacture of the cereal-based beverage concentrate, about 1 oz. of the furfuryl and alcohol solution is used for each 8 lbs. of the final dried product. In either case, a beverage especially acceptable to some tastes may be obtained by adjusting the pH to about'5 by the addition of citric acid or the like.

Having fully described our invention, it is to be understood that we do not wish to be limited to the details .set forth, but our invention is of the full scope of the appended claims.

No references cited. 

1. BIS-(2-PYRROLEMETHYL) DISULFIDE. 